Effective and economical burn-in screening is important for technology development and manufacture of semiconductor lasers. We study the burn-in degradation behavior of wavelength-division multiplexing semiconductor lasers to determine the feasibility of short burn-in. The burn-in is characterized by the sublinear model and correlated with long-term reliability

Jia-Sheng Huang

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Advances in OptoElectronics
Volume 2013, Article ID 568945, 4 pages
http://dx.doi.org/10.1155/2013/568945
Research Article
Burn-In Aging Behavior and Analytical Modeling of
Wavelength-Division Multiplexing Semiconductor Lasers: Is the
Swift Burn-In Feasible for Long-Term Reliability Assurance?
Jia-Sheng Huang
Emcore, Broadband Division, 2015 W. Chestnut Street, Alhambra, CA 91803, USA
Correspondence should be addressed to Jia-Sheng Huang; jshuang@emcore.com
Received 16 September 2013; Revised 7 November 2013; Accepted 8 November 2013
Academic Editor: Michele Norgia
Copyright © 2013 Jia-Sheng Huang. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Effective and economical burn-in screening is important for technology development and manufacture of semiconductor lasers.
We study the burn-in degradation behavior of wavelength-division multiplexing semiconductor lasers to determine the feasibility
of short burn-in. The burn-in is characterized by the sublinear model and correlated with long-term reliability.
1. Introduction
As the demand of data, voice, and video play grows, the
bandwidth requirement for downstream and upstream trans-
missions continues to increase. Recently, there has been accel-
erated growth in bandwidth demand due to the introduction
of mobile smart phones and portable touch screen tablets
(iPhone, iPad, etc.). Wavelength-division multiplexing has
been the enabling technology for higher bandwidth. To meet
the WDM applications where a high density of channels
is in service, each channel requires superior reliability and
wavelength stability. Some network and cable operators have
tightened up their wavelength stability from 0.1 nm to 0.03–
0.09 nm [1–4]. On the other hand, there has been an ongoing
driver to reduce the manufacturing cost and cycle time of the
laser components. One way to achieve the lower cost is by
means of qualification improvement.
In this paper, we study the burn-in behavior of the
WDMdistributed feedback (DFB) lasers and correlate it with
long-term reliability. We characterize the burn-in behavior
using sublinear model and determine the burn-in times. We
also correlate the burn-in with the long-term life test. We
demonstrate that swift burn-in screen of BH lasers is feasible
while meeting the long-termWDM reliability requirement.
2. Experimental
The buried heterostructure (BH) DFB lasers with C-band
(1550 nm and vicinity) lasing wavelength were used for the
study. Epitaxial layers were grown on n-type InP substrate
using metal organic chemical vapor deposition (MOCVD)
technique. First, n-doped InP buffer layer was grown. An
active layer consisting of multiquantum well structures and
grating layers were grown sequentially. The composition of
the active region was InGaAsP. A mesa structure was formed
by wet etch. Subsequently, p-InP and n-InP burying layers
were grown to form current blocking. The final regrowth
layer was grown, etched into mesa structure, and covered
with SiNx/SiO2 dielectric layers. The contact opening in the
dielectric was created by reactive ion etching (RIE), and the
p-metallization stack of Ti/Pt/Au/Cr/Au was deposited to
make ohmic contact. On the n-side, the wafer was thinned by
lapping and deposited with AuGe/Ni/Au to form n-contact.
Finally, wafers were cleaved into bars to form facets, and the
bars were coatedwith antireflective (AR) and highly reflective
(HR) coatings. The laser cavities of 550 and 1000 micrometer
were prepared for burn-in and life test studies.
Chips were die attached and wire bonded to the AlN sub-
mounts to facilitate burn-in and life test [5]. The burn-in and
2 Advances in OptoElectronics
Case A
Burn-in time (hour)
It
h c
ha
ng
e (
m
A
)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Fully stabilized
0 12 24 36 48 60
(a)
Case B
It
h
 ch
an
ge
 (m
A
)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Fully stabilized
Burn-in time (hour)
0 12 24 36 48 60
(b)
Figure 1: (a) Case A burn-in behavior of WDM lasers. The laser cavity is 550 micrometer from wafers A and B. (b) Case B burn-in behavior
of WDM lasers. The laser cavity is 550 micrometer from wafer C.
life test were monitored with high-resolution measurements
on the threshold current, optical output power, and forward
voltage. The burn-in and life test aging was conducted at
100∘C, while the LIV (light versus current, voltage) data was
taken at 25∘C at every interval. The LIV was measured in situ
throughout the aging test in order to minimize the noises
introduced from external handling. At each interval, the laser
submounts were cooled down to 25∘C by the thermoelectric
cooler (TEC) and stayed at 25∘C for 5 minutes to allow full
temperature stabilization before LIV data was taken.
3. Results and Discussions
The lasers of 550-micron cavity were subjected to the burn-
in stress current of 210mA at 100∘C. To determine the time
for lasers to stabilize, the LI was taken at every 6 hours.
The typical burn-in behaviors are shown in Figures 1(a) and
1(b). For case A, the lasers showed gradual increases in the
threshold current (Ith) during 0–12 hours and became fully
stabilized after 12 hrs. For case B, the lasers showed gradual
Ith increases during 0–24 hours and became fully stabilized
after 24 hrs. The burn-in behavior showed dependence upon
the wafer. The processing was nominally the same. Case A
behavior came from the samples of wafers A and B, while case
B was from wafer C.
The burn-in curves in Figure 1 were also characterized
by the sublinear fitting. The sublinear model was based on
polynomial function expression recommended by Telcordia
[6]. In the sublinear model, an experimental burn-in curve
was fitted by 𝑦 = 1 + 𝑎𝑡𝑚 where 𝑦 is the ratio of the
threshold current at time (𝑡) after burn-in and the initial
threshold current, 𝑡 is the burn-in time, and the constant (𝑎)
and the exponent (𝑚) are the free parameters for the curve
fitting [7–10]. Table 1 shows the fitting exponent and fitting-
correlation factor of the two groups. For case A, the smaller
fitting exponent suggests a greater saturation of threshold
current. This is consistent with the earlier time (12 hours)
Table 1: Sub-linearmodel fitting extrapolation of burn-in curves for
cases A and B.
Case A Case B
Fitting exponent 𝑚 = 0.2 𝑚 = 0.4
Fitting-correlation factor 𝑓 = 0.961 𝑓 = 0.865
𝐼th stabilization At 12 hr At 24 hr
𝑅 square 0.967 0.874
Sample size 4 5
of Ith stabilization in case A compared to the 24 hr in case
B. The statistical uncertainties are estimated by 𝑅 squares.
An analytical simulation by Lam et al. [11] showed that
the sublinear model was accurate in describing the saturation
of degradation in aging curves. It was assumed that the
change in threshold current was given by the change in the
nonradiative recombination current that was proportional to
the defect density. It was further assumed that the source
to supply the creation and growth of defects was finite.
Figure 2 shows the example of simulated degradation curves
as a function of curve fitting exponent (𝑚). As 𝑚 increases,
the aging curve becomes more linear with less degree of
saturation. On the other hand, the saturation becomes more
pronounced when m is smaller, as shown in case A.
Figure 3 shows the threshold current (Ith) change as a
function of stress current density. The current density is
defined as the current divided by the cavity length. The Ith
change generally increases with increasing current density.
The higher current density would accelerate the aging rate
likely due to the enhanced defect formation and propagation.
The Ith change follows the linear regression line, suggesting
the same degradation mechanism without inducing new
failure modes. For a given burn-in current density, the Ith
change is higher for the l000 micrometer long lasers, likely
due to the long cavity and mechanical stress [12–16]. For the
long cavity, the number of defects within the laser cavity
is likely to be higher. In addition, the mechanical stress
Advances in OptoElectronics 3
Burn-in time (hour)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0 12 24 36 48 60
m = 0.2
m = 0.1
m = 1.0
m = 0.2
m = 0.3
m = 0.5
m = 0.7
m = 1.0
It
h
(t
)/
It
h
(0
)
−
1
Figure 2:The sublinear fitting curve as a function of fitting exponent
(𝑚). The saturation is more pronounced when𝑚 is smaller.
Burn-in current density (mA/𝜇m)
It
h
 sh
ift
 (m
A
)
1.5
2.0
2.5
3.0
3.5
4.0
0.3 0.4 0.5 0.6 0.7
24hr burn-in
550𝜇m
1000 𝜇m
Figure 3: Ith change versus stress current density of WDM lasers of
550- and 1000-micron lengths.
caused by themismatch of the thermal expansion coefficients
between the InP laser chip and AlN submount becomes
more important as the laser cavity increases [13]. Hence, the
degradation rate is expected to be higher.
We also correlated the burn-in behavior and long-term
life test aging. In order to complete the life test study in a
reasonable time frame, we used the first 300-hour life test data
for the correlation analysis. Figure 4 shows the correlation
of the threshold current changes between the burn-in and
life test aging where the linear regression line and the 95%
confidence intervals are shown by the solid line and dash
lines, respectively. The coefficient of determination, denoted
as 𝑅 squared, was 0.87.The burn-in (BI) degradation rate was
defined as the ratio of the Ith change and burn-in time. The
accelerated life test (ALT) degradation rate was defined as the
A
LT
 It
h
 d
eg
ra
da
tio
n 
ra
te
 (m
A
/h
r)
0.00
0.02
0.04
0.06
0.08
95% confidence intervals
−0.02
Slope = 0.42
R2 = 0.87
−0.06 −0.04 −0.02 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14
BI Ith degradation rate (mA/hr)
Figure 4:Correlation of burn-in and life test aging.Theburn-in and
subsequent life test degradation rates are correlated.Thedegradation
rate is decreased over time. The solid and dash lines indicate the
linear regression and 95% confidence intervals, respectively.
ratio of the Ith change and ALT aging time.The Ith change of
ALTwas generally proportional to the Ith change of BI. Based
on the fitting regression, the slope was 0.42, suggesting that
the degradation was slower during life test aging. This was
consistent with the sublinear model where the degradation
rate was expected to decrease over time.
4. Conclusion
We studied the burn-in behavior of theWDMsemiconductor
lasers by using the sublinear model. case A group showed Ith
stabilization at 12 hr, while case B group stabilized at 24 hr.
The former showed a greater saturation in degradation rate,
leading to a smaller fitting exponent (𝑚). The life test Ith
change also showed correlation with the burn-in Ith change.
The ratio was determined to be 0.42, indicating that the
degradation was saturating over time.We have demonstrated
that swift burn-in screen (<48 hr) may be feasible.
References
[1] B. E. A. Saleh and M. C. Teich, Fundamentals of Photonics,
Wiley, 2nd edition, 2007, Chapter 22.
[2] J.-S. Huang, “Design-in reliability of modern distributed
feedback (DFB) InP lasers: can we meet up the stringent
wavelength-division multiplex (WDM) requirement?” in Pro-
ceedings of the IEEE Photonics Society Summer Topical Meeting
Series, pp. 89–90, Montreal, Canada, July 2011.
[3] H. Takaaki, H. Mamoru, and N. Hideki, “Wavelength-stable
laser diode and photodiode array for laser interferometer
positioning systems,” Technical Report no. 32, Yokogawa, 2001.
[4] D. A. Cohen and L. A. Coldren, “Temperature compensation
of the threshold current, differential efficiency, and refractive
index of a GaInAs/InP MOW diode laser mounted on a
bimetallic heatsink,” Electronics Letters, vol. 32, no. 24, pp. 2245–
2247, 1996.
[5] J.-S. Huang, T. Nguyen, W. Hsin, I. Aeby, R. Ceballo, and
J. Krogen, “Reliability of etched-mesa buried-heterostructure
4 Advances in OptoElectronics
semiconductor lasers,” IEEE Transactions on Device and Mate-
rials Reliability, vol. 5, no. 4, pp. 665–674, 2005.
[6] Telcordia Technologies, “Generic reliability assurance require-
ments for optoelectronic devices used in telecommunications
equipment,” GR-468-CORE, Bellcore, 1998.
[7] S. P. Sim, “A review of the reliability of III–V opoelectronic
components,” in Semiconductor Device Reliability, A. Christou
and B. A. Ungar, Eds., vol. 175 ofNATOASI Series, pp. 301–3319,
Kluwer Academic, Dodrecht, The Netherlands, 1990.
[8] J.-S. Huang, “Temperature and current dependences of reli-
ability degradation of buried heterostructure semiconductor
lasers,” IEEE Transactions on Device and Materials Reliability,
vol. 5, no. 1, pp. 150–154, 2005.
[9] Y. Deshayes, L. Bechou, F. Verdier, and Y. Danto, “Long-term
reliability prediction of 935 nm LEDs using failure laws and
low acceleration factor ageing tests,” Quality and Reliability
Engineering International, vol. 21, no. 6, pp. 571–594, 2005.
[10] M. S. Ab-Rahman and M. R. Hassan, “Theoretical analysis of
the effect of temperature dependence of Auger coefficient on the
turn-on time delay of uncooled semiconductor laser diodes,”
Optics Communications, vol. 283, no. 11, pp. 2378–2384, 2010.
[11] S. K. K. Lam, R. E.Mallard, andD. T. Cassidy, “Analytical model
for saturable aging in semiconductor lasers,” Journal of Applied
Physics, vol. 94, no. 3, pp. 1803–1809, 2003.
[12] J. S. Huang, “Design-in reliability for modern wavelength-
division multiplex (WDM) distributed feedback (DFB) InP
lasers,” Applied Physics Research, vol. 4, no. 2, pp. 15–28, 2012.
[13] T.Westphalen,M. Leers,M.Werner,M. Traub, H. d. Hoffmann,
andR.Ostendorf, “Packaging influence on laser bars of different
dimensions,” inThe7thHigh-Power Diode Laser Technology and
Applications, vol. 7198 of Proceedings of SPIE, San Jose, Calif,
USA, 2009.
[14] S. Landi, C. Papuzza, A. Piccirillo, D. Re, and L. Serra, “Char-
acterisation of III–V optoelectronic devices by internal second-
harmonic generation technique,” Applied Surface Science, vol.
143, no. 1, pp. 115–123, 1999.
[15] J.-P. Landesman, “Micro-photoluminescence for the visualisa-
tion of defects, stress and temperature profiles in high-power
III–V’s devices,”Materials Science and Engineering B, vol. 91-92,
pp. 55–61, 2002.
[16] T. M. Alander, P. A. Heino, and E. O. Ristolainen, “Analysis of
substrates for single emitter laser diodes,” Journal of Electronic
Packaging, vol. 125, no. 3, pp. 313–318, 2003.
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Burn-In Aging Behavior and Analytical Modeling of Wavelength-Division Multiplexing Semiconductor Lasers: Is the Swift Burn-In Feasible for Long-Term Reliability Assurance?

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Burn-In Aging Behavior and Analytical Modeling of Wavelength-Division Multiplexing Semiconductor Lasers: Is the Swift Burn-In Feasible for Long-Term Reliability Assurance?

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